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Extended Site Characterization Report: 7500 West Eleventh Street, Tracy, Cit. Page 23 r� Assume Specific Gravity of Diesel = 0.84 Assume Specific Gravity of Gasoline= 0.74 Assume relative proportions of diesel and gasoline in the floating product in Monitoring >=: Well MW-7 are in the same ratio as the concentrations of diesel and gasoline in the sample of groundwater recovered from that well on December 13, 2001. They were, - respectively, 800,000 µg/L and 61,000 µg/L. (See Table 4.) Thus, the estimated specific gravity of the floating product in Well MW-7 is: PP =0.83 The depression in the elevation of the water table due to the presence of floating product is given by: =' W= T (pp 1p,) (Equation 1) Where: W= the depression of the water table T = the thickness of floating product in the monitoring well per, = the specific gravity of the groundwater ` PP = the specific gravity of the floating product j Thus, in the case of the floating product measured in Well MW-7 on April 11, 2002: W= 0.3 (0.83/1.0) = 0.25 ft. �i Accordingly, when drawing the contours shown on Figure 8, the elevation of the groundwater in Well MW-7 was based on an assumed depth to groundwater of 9.39 ft. rather than the depth of 9.64 ft. actually measured. Thisyields a corrected groundwater table elevation of 38.83 ft. MSL (which is shown on Figure 8) compared to the uncorrected value of 38.58 ft MSL given in Table 2. In addition, the groundwater elevations in Wells MW-3A, MW-3B and MW-12A were -- not considered when the groundwater contours were drawn because, although small in magnitude, differences in the elevations of the groundwater in Wells MW-3, MW-3A and MW-313 and in MW-12 and MW-12A are sufficiently great to indicate that the groundwater monitored by the shallow well at the locations of each of those well clusters has different pieziometric pressures than that in the deeper wells in the same cluster and sic